Hi,
What would that do, exactly?
You can post messages to any Google Group by emaling to its address: e.g. "android-developers@googlegroups.com" (this is on the bottom of each message in that group, btw).
Am I missing something?
Are you asking how to add it to your device's contacts list, so it autocompletes? Just use the Contacts/People app to add an entry, and configure its email as "android-developers@googlegroups.com".
Am I still lost?
Please clarify.